I. Field of the Invention
The present invention relates to fluid flow meters.
II. Description of the Prior Art
There are a number of previously known fluid flow meters for measuring and indicating the flow rate of a fluid. For example, in one type of previously known flow meter, a semicircular vane cooperates with a hemispherical wall so that a variable size opening is formed between the vane and the wall depending upon the rotational position of the vane. The fluid flows from an inlet, through the variable size opening and out through the flow meter outlet. The rotational position of the vane, and thus the flow rate through the flow meter, is displayed on a scale which is visible exteriorly of the flow meter. There are also many other types of fluid flow meters.
These previously known fluid flow meters, while accurate and satisfactory in operation, are relatively expensive in construction. Furthermore, for many flow meter applications it is necessary only to determine whether the flow rate to the flow meter is within a predetermined flow range. Consequently, the high accuracy obtained by these previously known flow meters is not required for such applications.